The invention relates generally to the melting of substances and, more particularly, to a method and arrangement for melting particulate materials.
The melting of scrap is known from the U.S. Pat. No. 3,775,544. Here, a column of scrap is formed in a vertically arranged melting chamber. A burner lance is located on the axis of the melting chamber and may extend into the latter either through the column of scrap or through the bottom of the chamber. The burner lance generates a plate-shaped flame which is directed against the lower end of the scrap column from below the latter. The flame is centered with respect to the scrap column and extends over the greater part of the cross-section of the same. In this manner, the scrap is continuously melted by the high temperature burner in a counter-current manner, meaning that fresh scrap moves downwardly through the melting chamber as the lower end of the scrap column melts to thereby become exposed to the action of the flame. The flame is positioned at such a distance above the bottom of the melting chamber that the molten material which continuously flows off is able to form a thermal barrier for the heatresistance lining of the melting chamber.
The molten material has a temperature which is only slightly higher than the liquidus temperature. This poses a discontinuous partially disadvantage when the molten material must be transported from the melting chamber to a converter, a Siemens-Martin oven or the like for further processing. Moreover, this may lead to blockage of the outlet opening of the melting chamber by molten material which has solidified. The latter is particularly the case when the molten material is to be further processed in a continuous operation so that the melting operation must be broken off. Thus, the molten material will solidify by virtue of the fact that the scrap column is particulally immersed therein so that heat is removed from the molten material.
Further known from the U.S. Pat. No. 2,382,534 is a melting chamber for melting scrap packets or briquettes. Here, the scrap packets are held in a charging shaft which is narrowed at a lower end thereof to fall from there into a bath of molten material where they are melted. This implies that within the molten material a temperature is maintained, not substantially exceeding the liquidus temperature so that difficulties arise when the molten material is tapped off, as the molten material has the tendency to freeze at the tapping holes because of the little difference between liquidus temperature and solidification temperature.
From the German Democratic Republic Pat. No. 21,760, there is also known an oven for the melting of iron and, in particular, pig iron. The oven is provided with a charging shaft of small dimensions and the charge descends through the roof of the oven to leave the charging shaft in conical manner and sink into the melt. Here, also, there is a large heat transfer between the molten material and the charge.